Analysis of Construction Disturbance Measurement of Three Lane Rectangular Pipe Jacking Tunnel with Small Clear Distance

The on-site measurement and analysis were conducted on the internal force, soil pressure, jacking force, vertical attitude, and surface settlement caused by the construction of a 1.2 m ultra-small clear distance three-lane pipe-jacking rectangular tunnel under the Jiaxing Ring Road, which passes through Nanhu Avenue. During the later implementation of tunnel excavation, the internal force of the double line pipe-jacking of rectangular tunnel fluctuated due to posture adjustment and the effect of lubricating mud. As the tunnel construction approaches, the internal force of the previous pipe weakens, strengthens, and then recovers, resulting in a maximum reinforcement stress increase of about 30%; Compared with conventional single-line rectangular pipe jacking, the surface settlement caused by construction exhibits a relatively flat peck settlement curve, and the maximum settlement was concentrated on the originating well side, showing a certain drag effect as the jacking distance increases; The main factor of the settlement difference between the north and south lines was the vertical attitude control of tunneling, and the jacking force did not show a large difference due to the small clearance.